Conditioned display



May 13, 1941. K. w. HALL Erm. 2,241,353

CONDITIONED DI SPLAY Filed March 9, 1938 2 Sheets--Sheel 1 ATTORNEYS May 13, 1941. K. w. HALL ETA.

CONDITIONED DISPLAY Filed March 9, 1938 2 Sheets-Sheet 2 ATTORN EYS Patented May 13, 1941 CONDITIONED DISPLAY Keitll, W. Hall and DonaldW. McCready, Ann Arbor, Mich.; said Hall assigner to Tolco, Inc., Toledo, Ohio, a corporation of Ohio Application March 9, 1938, Serial No. 194,802.

Z Claims.

The invention relates to the conditioned display, particularly in retail stores, of products of the soil, cigars and other products that require a humid or refrigerated atmosphere.

In the retailing of produce it Vhas been found highly essential that piles or masses of the produce be kept in full view, and also that the produce be unenclosed so that customers may handle it. The great majority of consumers make a practice of visiting more than one store, and the stores that provide the most effective displays sell the most produce. It is universally found that a retailer sells more produce by displaying it on open racks than by displaying it behind glass, because the customers urge to buy is fostered by displaying the produce in the open where he can reach out and pick it up.f

Under ordinary atmospheric conditions, however, produce displayed in the open air suffers rapid wilting and loss of freshness because it dries out. Attempts have been made to protect produce on open racks against dehydration by the use of a fine spray to keep it continually wet, but keeping produce wet causes it to become slimy so that it loses its salability about as fast as it does when it is simply left in the 'open air.

The principal object of the invention is the protection of products against deterioration on open display. More specific objects and advantages are apparent from the description, in which reference is had to the accompanying drawings illustrating preferred embodiments of the invention.

Fig. I is a vertical section of a display rack embodying the invention;

Fig. II is a vertical section of a modified form thereof;

Fig. III is a vertical section of a further modified form thereof; f

Fig. IV is a vertical section of a further modiiication;

Fig. V is a vertical section showing a modified. form of display rack located in a show window;

Fig. VI is a perspective view of a preferred form of display rack divided into separate compartments;

Fig. VII is a transverse vertical section thereof, taken on the line VII- VII of Fig. VI;

Fig. VIII is a fragmentary vertical section taken on the line VIII- VIII of Fig. VII;

Fig. IX is a fragmentary vertical section taken on the line IX-IX of Fig. VIII.

These specific drawings and the specific description that follows merely. disclose and illustrate the invention, and are not intended to im'- -pose limitations upon the claims.

Humid air substantially free from water particles is a satisfactory medium for protecting products of the soil against rapid dehydration on display. When the air that surrounds the products has been refrigerated, the relative humidity of the air does not need to be as high as when the air is warm, because moisture does not evaporate from produce as rapidly into cold air. Refrigerated air is also useful in retarding the growth of molds and bacteria.

When conditioned air is supplied to produce on open display racks, however, the eddies and convection currents that normally exist in the room mix With and dilute the conditioned air and sweep it away from the surface of the produce with surprising rapidity, so as to destroy the protection that the conditioned air affords.

It has been discovered that produce on display can beffully protected if, in acordance with the invention, the produce and a space thereabove are shielded against the entry of atmospheric air without material impairment of the free accessibility of the produce, while air having a relative humidity substantially higher than that ordinarily prevailing in the atmosphere is supplied to the produce without wetting it, the produce and the space thereabove being shielded to a sufiicient extent and the humid air being supplied at a sumcient rate to maintain the relative humidity of the air in the shielded space substantially above that ordinarily prevailing in the atmosphere.

The invention is based upon the discovery that it is possible to protect the produce by supplying conditioned air to a shielded space above it, Without supplying excessive amounts of humid air so as to steam up the room, and without actually enclosing the produce., The produce re-` mains fully visible to customers, and it is actually in the open so that customers can reach out and pick it up.

In the practice of the invention the relative humidity of the air in the shielded space above the products is preferably substantially higher than that ordinarily prevailing in the surrounding atmosphere, i. e., enough higher so that products of the soil keep appreciably better than they do in contact with the atmosphere of the room. The air that is supplied should be substantially free from liquid particles; in other words, liquid particles in thev air should be so few that they evaporate quickly after being deposited upon the displayed products instead of keeping the -products wet. Since produce is frequently received by retailers in wet condition, there should be an arrangement for temporarily supplying air of lower `relative humidity to the rack, or to parts of the rack, for the purpose of drying off wet produce that has been placed on the rack.

The supplying of the conditioned airmay create a slight pressure within the shielded space that helps to inhibit the entry of atmospheric air. Air may be withdrawn from the shielded space, reconditioned and recirculated, but it is preferable that a certain amount of atmospheric air be taken into the conditioning apparatus at all times so that conditioned air is always being exhausted from the shielded space into the room.

It has been discovered that when refrigerated air is supplied to an ordinary open rack it becomes heated up rapidly because of the fact that the rack is fully exposed. As the refrigerated air becomes Warmer in passing among products on the rack, its relative humidity falls rapidly, so that it dehydrates the products even more severely than the room air.

Devices embodying the invention are advantageous in that they prevent refrigerated air that has been supplied to the products on display from being heated up while it is still in contact with the products. The confined body of conditioned air above the products can be kept at the desired low temperature by supplying the conditioned air at the proper rate, because the entry of atmospheric air into the shielded space is substantially prevented. Because of the body of cool ,air above the products, refrigerated air that is supplied to the products does not become heated up as it flows among them.

When the apparatus operates at refrigerating temperatures it should be well insulated and the conditioned air should be supplied in relatively large quantities. Because of they large volume of air required when the air is refrigerated, it is preferable to recirculate a portion of the air from the shielded space to the conditioning apparatus. When the refrigerated air from the conditioning apparatus is discharged directly among the products a sufficient volume of air should be recirculated to the conditioning unit from the shielded space to prevent the refrigerated air from undergoing a material temperature rise as it passes among the products. In addition to the volume of air that is recirculated, suiiicient air should be passed from the atmosphere through the conthe humiditled air never cools the produce sutilciently to cause condensation thereon.

Retailers remove produce from ordinary display racks each evening and replace it each morning because they appreciate the rapidity with whichv the produce deteriorates on the racks. This custom makes it necessary that all the produce be handled twice each day, and such handling causes serious spoilage losses as well as impairment of the appearance of the produce, by breaking of stems, etc. 1

Apparatus embodying the invention may be covered at night or whenever the produce is not being displayed, and the discharge of conditioned air into the atmosphere may be reduced while the rack is covered. If desired, the arrangement may be automatic, so that the positioning of the cover on the rack actuates the mechanism for reducing the discharge of conditioned air into the atmosphere. vOi? course the discharge of conditioned air into the atmosphere of the roomV and the load upon the conditioning ditioning apparatus to the display rack so that the temperature in the shielded space can be maintained substantially below that of the atmosphere, this air being supplied to cause an equal volume of conditioned air to be exhausted from the shielded space into the room.

Of course it is possible to obtain quite satisfactory results by supplying to an apparatus emtially its wet bulb temperature, which may be 5 to 20 F. below the temperature of the air before humidication. Since the wet bulb temperature of air thatA is withdrawn from the atmosphere for humidication is always greater than the dew point temperature of the atmosphere,

apparatus may be reduced by simply recirculating the air while the rack is covered. It is desirable for a retailer to cover the rack at night in order to avoid steaming up his store While there ls no one entering or leaving through the door and, therefore, little ventilation of the store. If desired, a piece of canvas or other cloth may be thrown over the rack to cover it up and shut out the air of the room.

In accordance with the invention, an access opening of maximum size may be used if a shielding means is employed that consists wholly or in part of an air curtain, i. e., a substantially continuous sheet of rapidly moving air. Any eddies or drafts that might otherwise cause atmospheric air to enter the enclosure are overcome by the air curtain, so that dilution of the conditioned air in the shielded space by atmospheric air is inhibited.

The stream of air forming the curtain is narrowest near the point of discharge because the stream tends to become wider and wider as additional air is entrained. In fact the air curtain consists not of air moving in a single direction but air moving with considerable turbulence. This stream of air entrains air from the enclosure on one side and air from the atmosphere on the other side.

It is preferable that the curtain of air be so directed that it does not enter the shielded space. When no portion of the air curtain is directed into the shielded space, the air that is entrained from that space causes a continuous loss of conditioned air. If this loss of' air occurs at too high a rate, there may be a tendency for atmospheric air to flow into the enclosure at certain points to replace it. In accordance with the invention, therefore, the curtain of'air is discharged at a velocity suflicient to inhibit the entry of atmospheric air but low enough so that air is not lost from the shielded space faster than conditioned air is supplied thereto.

When the curtain of air is so directed that it does not enter the shielded space, the condition of the air that is discharged to form the curtain is not material and the air used to form the curtain may be taken directly from the atmosphere ,without conditioning. However, it is permissible to use conditioned air for the curtain. If a suiiicient volume of conditioned air is discharged in the form of a curtain, the curtain itself serves to condition the space above the products and no additional conditioned air needs to be supplied to the shielded space. n such a case it is permissible to direct the curtain of conditioned air achete so that a portion of the conditioned air is discharged into the shielded space.

The total discharge of conditioned air into the room from an apparatus embodying the invention is not great enough to cause excessive humidiiicatiori of the room when the maximum volume of conditioned air necessary to maintain the required humidity in the shielded space is suppliedto the apparatus.

In the preferred constructions, conditioned air is supplied to products of the soil on display by injecting it into the bed of products on the rack so that it permeates and flows through the bed. The air iiowing through the bed of products continually displaces air from the shielded space thereabove and thus helps to protect the products against dehydration. 'I'he continual permeation of the bed oi' products by conditioned air in itself protects all of the products except those that are exposed at the top of the bed, and the exposed products are protected by the body oi. conditioned air in the shielded space.

It should be noted that living produce carries on a process of respiration, in which process oxygen is absorbed from the air and water and carbon dioxide are evolved. The water that is generated by respiration must be continually evaporated from the produce to prevent the surface of the produce from becoming waterlogged. To allow the water of respiration to evaporate, the air surrounding the produce should not be completely saturated.

Produce that is being properly kept undergoes a continual small loss of Weight, but, in accordance with the present invention, the loss of weight by evaporation may be controlled even when the produce is on open display. 'Ihe total loss of weight by evaporation of moisture from produce that occurs in a gradual manner within the space of twenty-four hours in the practice of the present invention does not cause the appearance of the produce to suier materially, but the same total loss, if allowed to take place rapidly within the space of a few hours, would cause serious deterioration in the appearance of the produce.

The air that is discharged through the bed of products on a rack is preferably conducted to the rack through a passage, such as the orice plate I of Fig. I, which is restricted to render the pressure drop that occurs as the air passes through the bed, even when the rack is full, so insignificant compared to pressure drop in the passage that variations in the rate of airflow caused by variations in the amount of products on the rack have no effect of any importance upon the products. The use of such a restricted passage for discharging the air into the bed of products greatly increases the resistance to the airow, and makes it necessary to employ a larger blower and to supply the air under a higher pressure than if the air were supplied directly to the rack. However, the restricted passage is highly advantageous in that the rate of airflow is little aiiected by the pressure drop in the bed of products. Without the restricted passage, the air would ow through the rack at a high rate when the rack was nearly empty and at a low rate when the rack was full. 'Ihe resistance to the airflow offered by the restricted passage is so great that the resistance met by the air as it flows through the rack beyond is relatively unimportant.

In'Fig. I the aperture in the orifice plate I0 is of such a size that the air supplied thereto under pressure ows at the proper rate into the hooded enclosure Il through the perforated false bottom l2 on which the products are supported. 'Ihe conditioned air is supplied by a duct I3 and after flowing upward through the products lls the enclosure ll and escapes through the access opening i4. The enclosure Il is provided with a glazed portion l5 to make the products more fully visible.

In the device of Fig. II a hood I1 is suspended by means of hangers I8 above the produce rack i9. Humidied air is supplied through a duct 2li to the space enclosed by the hood, and the supply of air to be humidied is withdrawn from the enclosed space through four at return ducts 2l, leading to a main return duct 22. In the devices of Figs. I and II the space above the products on display is shielded to a suiiicient extent so that a body of conditioned air substantially undiluted by air from the atmosphere can be maintained Within the shielded space.

The rack of Fig. III is shielded by means of sheets of moving air that enclose a space above the rack. The shielding currents of air are discharged from four branch ducts 23 fed by a main supply duct 2t. A vertical extension 25 of the main supply duct 24 leads air into the space beneath a. false bottom 26 that supports the produce, and discharges a vertical column of air through a nozzle 28 for further inhibiting the entry of atmospheric air into the shielded space.

Fig. IV shows a rack that is similar to the device of Fig. III with the exception that air is injected into the mass of produce through an auxiliary duct 21 that is separate from the main supply duct 2li. These ducts are made separate so that the air supplied by one duct can have a temperature and relative humidity different from that of the air supplied by the other duct. For example, the air discharged from the branch ducts 23 to shield the space above the produce may be considerably warmer than the air that is supplied by the auxiliary duct 21.

In any case, however, the temperature and re1- ative humidity of the air supplied through the main duct 2t and the auxiliary duct 21 should be such that the body of air immediately above the produce has a relative humidity substantially above that of the atmosphere. In other words, the mixing of the air supplied through the auxiliary duct with some of the air discharged to form the curtains should produce a body of air having a relative humidity high enough so that the produce is protected `against dehydration. Thus the device of Fig. IV, like that of Fig. III, is provided with means for supplying air having a relative humidity substantially above that ordinarily prevailing in the atmosphere, and apl paratus for discharging air curtains, constituting a means for shielding the rack and a space thereabove against the entry of atmospheric air without materially impairing the free accessibility of the products.

The perforations in the upper end of the auxiliary duct 21 should be small enough in size and few enough in number to restrict the flow of air in the same manner yas the orifice plate l0 in Fig. I.

If the rack of Fig. III or Fig. IV is placed against a wall, the branch duct 23 on the side of the rack adjacent the wall can be omitted, the air curtain from the opposite side being directed upward by the wall in the manner illustrated in Fig; V. The wall shields the space above the rack on one side and makes it unnecessary to employ an air curtain on that side.

The rack of Fig. V is located behind the show window in a store front. A single air curtain indicated by the arrows is employed and there is a shielded body of air beneath this air curtain and above the produce. The produce is visible through the window to people in the street and is freely accessible to customers in the store.

It should be noted that the air curtains in Figs. III, IV and V are so directed that they do not enter the shielded space above the products. 'I'he arrangement shown in Fig. V is advantageous in the summer because the curtain of air is deflected upward along the glass window and carries heat away from the window.

The rack illustrated in Figs. VI and VII is divided into two tiers, with a longitudinally extending opening at the front of each tier.` Extend-` ing transversely across lboth tiers are partitions 29, which have been found -to be helpful toward inhibiting the entry of atmospheric air in that they prevent air currents from flowing longitudinally of the rack. Perforated false bottoms 30 are provided and humidied air is supplied to the space beneath them. The transverse partitions 29 divide each of the two tiers into three compartments, and the right-hand compartment in the vlower tier is shown with an imperforate bottom 3l'. This compartment can be used for the display of products, such as dried fruits, that do not need to be protected against dehydration.

It should be noted that fresh produce, to which the invention is particularly applicable, differs from dried fruits and the like, in -that a fresh vegetable or fruit may be considered a living organism because it breathes or respires by taking in oxygen and giving off carbon dioxide. If fresh produce is to remain in salable condition, it must be kept alive and healthy, because it rapidly wilts, shrivels or becomes slimy as the result of suiocation, excessive dehydration, or remaining wet for an extended period. Produce is suiocated by keeping it wet, because a lm of Water on the surface of a vegetable or fruit shuts ofi` the breathing pores from the air.

Beneath the imperforate bottom 3i of the lower right-hand compartment are a motor 32` and blower 33 mounted on a base 34, for supplying air to the other five compartments. Filling the bottom of the apparatus,`with the exception of the corner that is partitioned off for the blower and motor, is a body of water that supplies the moisture for humidification of the air. Air from the blower compartment is discharged by the blower 33 through the adjustable orifice I6 and flows above the surface of the water into a at vertical duct 35 that occupies the entire rear Wall of the apparatus. After leaving the vertical duct 35, the air passes downward through an intermediate duct 36 of the same size, and then upward into a distribution duct 31. Located in the ducts 35 and 36 are the centrifugal atomizing discs 38 that dip into 4the water in the bottom of the apparatus. The discs 38 are mounted upon a shaft 39 connected with the blower and motor shafts, and spray Water throughout the entire extent of the ducts 3-5 and 036 as they rotate.-

The duct 36 is provided with a short downwardly extending leg behind the blower comparti ment, which is supplied with water from the main body of Water through an opening 40. Aftl er passing a mist separator 4| in' the distribution duct 31, a part of the humidified air ows through openings 42 into the spaces beneath the perforated false bottoms. 'I'he remainder of the humidifled air flows through a horizontal duct 43 and is discharged in the form of a curtain across the access openings of the upper tier oi compartments. In order that the curtain of air may not have a tendency to carry atmospheric air into the enclosure, it is directed outward at a slight angle tothe plane of the access openings.

The space above the products in the upper compartments is shielded to a considerable extent byfthe tangible structure above and behind thecompartments. Thus it may be permissible to cut off the discharge of the air curtains when the relative humidity of the surrounding atmosphere is high.

In order that a portion of the conditioned air may be recirculated from the humidii'led compartments, two longitudinally extending return ducts are provided, the rectangular duct 44 taking air from the three upper-compartments, and the triangular duct 45 taking air from the two lower humidied compartments. From these two return ducts the air passes to a vertical main return duct 46, whence it enters the blower compartment through an opening 41 controlled by a damper 48. Louvers 49 are also provided at the front of the blower compartment for admitting air from the atmosphere.

For cutting 01T the curtain of air when the re1- ative humidity of the atmosphere is sufficiently high, a second damper 50 is provided. The damper 5|] may be closed automatically, if desired, by a device responsive to the relative humidity of the atmosphere in the room. A port 5| is provided for replenishing the supply of water. Located above the refill port 5l is a handle 52 that operates a by-pass damper 53. Opening the by-pass damper causes unhumidied air to be discharged into the distribution duct 31 to dilute the humidied air and decrease the relative humidity of the air supplied to the compartments. When wet produce is received for display and is placed on the rack, the damper 53 is opened by means of the handle 52, and it is left open until the produce has been dried off. The produce should be stacked on the rack in such a manner that air can freely permeate the mass.

When produce compartments are as completely shielded -as those in the lower tier of Fig. VI, protecting air curtains may 'be unnecessary under ordinary climatic conditions. It is recommended that air of about -95 (preferably 95) per cent relative humidity at temperatures of L5-75 F. be forced up through each square foot of the vbed of produce in the lower compartments of Fig. VI at a rate between and 250 (preferably 200) cubic feet per hour when the recirculation damper 48 is closed. The openings into the compartments in the upper tier are larger than the openings below, so that shielding air curtains are desirable for the upper compartments.

When the discharge of air up through the procl-v uce in the upper compartments is at a rate of 200 cubic feet per hour per square foot of perforated plate and-'the recirculation damper 48 is closed, the air curtains are preferably made up of a discharge of air atl about 600 cubic feet per hour per foot of length of the curtains, owing at a discharge velocity of about 15 feet per second. At a few feetfromv the discharge openings the velocity of the air lstream is less than at the point of discharge, butis still great enough to overcome the normal convection currents in the room, which flow at velocities up to five feet per second.

Although the relative humidity in the upper compar-tments may be somewhat below the relative humidity or the air that is supplied to the compartments, the air curtains shield the compartments to such an extent that the relative humidity therein can be kept considerably higher than that ordinarily prevailing in the surrounding atmosphere.

Fig. VII shows a coil 55 through which a refrigerant may be circulated to keep the water reservoir at a temperature only a few degreesv above the freezing point. When refrigeration of the water in the reservoir is employed, the apparatus should be well insulated. The blower 33 may be operated at a higher speed when the refrigeration is used and the damper 48 should be kept open to recrculate a consider-able portion of the refrigerated air. The Volume of refrigerated air that is forced up through the products in the compartments is preferably suloient so that the air does not undergo a material rise in temperature in passing through the bed oi products, i. e., the temperature rise of the air in passing among the products should not be great enough to cause appreciable dehydration eby reason of the reduction in relative humidity incident to the rise in temperature.

The air -that is taken into the conditioning apparatus from the atmosphere passes through an air lter 56, the amount of air thus taken in from the atmosphere being equal to the amount of air that is exhausted from the display compartments into the atmosphere. The volume so exhausted should be sumcient to inhibit to the desired extent the entry of atmospheric air through the access openings. In the case of the upper compartments the amount by which the volume of air passing upward through the periorated bottoms 30 exceeds .the volume of air drawn into the return duct M should 'be substantially as great as the volume of air lost from the upper compartments by the entraining action of the air curtains. The amount oi resistance oiered by the air lter S to the passage of air therethrough governs the amount of air that is taken into the conditioning apparatus from the atmosphere. Therefore the frictional resistance met by the incomingair that passes through the filter should be just great enough so that the necessary minimum amount of air is taken in through the louvers 9 when the recirculation damper ed is wide open.

Although the air to be recirculated from the display compartments is withdrawn near the tops of the compartments by the recirculation ducts in the device of Fig. VI, it is possible to supply and withdraw the air in the opposite manner. Thus the conditioned air may be introduced at the top of the shielded space, as in the device of Fig. II, and the perforations in the compart- .ment bottom may be used solely for the withdrawal of air to be recirculated.

When the produce in the compartments is not being displayed to customers a cloth may be thrown over the device of Fig. VI in order to close the access openings. The recirculation damper 48 should be wide open, the air curtain damper 50 should be closed, and the blower speed may be reduced while the access openings are closed. v

Leafy produce is in general more diilicult to keep in salable condition than nonleafy produce such as fruit, cucumbers, potatoes and peppers: however, prevailing distribution practices are such that nonleafy produce is received in larger lots and remains in the hands of retailers for a longer period. Therefore, spoilage losses With nonleaiy produce are often higher than spoilage losses with leafy produce.

Produce kept in an apparatus such as that shown in Fig. VI remains salable for a longer time than produce kept on an open rack equipped with atomizers for spraying Water upon the produce. Moreover, the condition of produce on a rack provided with atomizers may not remain uniform, because of irregular distribution of the mist from the atomizers. The rapid dehydration that results from leaving produce exposed to the atmosphere and the sliming that results from keeping produce wet cause produce that has been kept on an open rack, with or without atomizers, to be decidedly inferior in appearance -to produce that has Ibeen kept in an apparatus embodying the invention. The results of storing produce on ordinary displ-ay racks, and on a rack constructed like the device oi Fig. VI, with the conditioned air supply recommended above, were compared in a series of experiments.

Tabulated below are the results of a typical experiment in which the rate at which produce lost weight by dehydration, and the number of days during which produce remained salable, in the apparatus of Fig. VI, and in open display racks with and without sprays to keep the produce wet were determined.

Per cenltgrf gesight lost Days of salabmty Type oi produce Device Spray Dry geg? Spray Dry V rack rack VI rack rack 19. 6 2 1 M 7. 3 Over 4 3 1% 7. 0 3% 2 2 9. 9 Over 4 3 1% 7. 2 Over 4 4 4 15. 6 2% 1% 1 1% 3% l; f 2 5. 7 Y .3 1 0. l Over 4 Over 4 2. 2 Over 4 Over 4 12.8 4

1.8 0ver4 Overi 0. 8 Over 4 Over 4 1. 8 Over 4 Over 4 5. 9 3 3 Celery cabbage.- Over 4 3 The embodiments of the invention that have been disclosed may be modified to meet various requirements.

Having described our invention, we claim:

1. An apparatus of the class described comprising, in combination, an open display rack for products of the soil, means for shielding the rack and a space immediately thereabove against the entry of atmospheric air without materially impairing the free accessibility of the products, including means for discharging a protecting curtain of air that is so directed that it does not enter said space, and means for supplying to said space conditioned air substantially free from liquid particles, the rack being shielded to a suicient extent, and said conditioned air being supplied at a suicient rate, to maintain. within said shielding means a body of conditioned air substantially undiluted by atmospheric air.

2. In an apparatus of the class described, in combination, an open display Tack, means for shielding the rack and a space immediately thereabove against the entry of atmospheric air withc out materially impairing the free accessibility of products on the rack, a source for supplying to said space conditioned air under pressure without wetting the products, and a passage through which said conditioned air ows into said space, which passage is so restricted that the pressure drop in said space, when filled with the products', is slight compared with the pressure drop in the passage, the rack being shielded to a suicient extent, and said conditioned air being supplied at a suilcient rate, to maintain within said shielding means a body of conditioned air substantially undiluted by atmospheric air.

3. A method of conditioning products on display that comprises shielding the products and a body of air thereabove against the entry of atmospheric air by discharging a protecting air curtain while so directing said curtain that it does not enter said body of air, and supplying to the products conditioned air substantially free from liquid particles, said air curtain being discharged at a velocity low enough to cause a loss from said body of air that is substantially no more rapid than the supplying of said conditioned air.

4. A method of conditioning products of the soil on display that comprises shielding the products and a body of air thereabove against the entry of atmospheric air by discharging a protecting curtain of air while so directing said air curtain that it does not enter said body of air, and supplying to the products-air substantially free from liquid particles having a relative humidity substantially higher than that ordinarily prevailing in the atmosphere, the products and said body of air being shielded to a suiiicient eX- tent, and said humid air being supplied at a sufficient rate, to maintain the relative hiunidity of said body of air substantially above that ordinarily prevailing in the atmosphere.

5. A method of conditioning products of the soil on display that comprises shielding the products and a body of air above them against the entry of atmospheric air without materially impairing the i'ree accessibility of the products, supplyinr *o the products air having a relative humidity substantially higher than that ordinarily prevailing in the atmosphere without keeping the products wet, and supplying the air at a lower relative humidity when the products are wet and until they have dried oil, the products and the body of air above them being shielded to a sufllcient extent, and said humid air being supplied at a suflicient rate, to maintain the relative humidity of said body of air substantially above that of the atmosphere.

6. A method of conditioning products of the soil on display that comprises shielding the products and a body of air above them against the entry of atmospheric air without materially impairing the free accessibility of the products, treating air to be supplied to the products to give it a relative humidity substantially higher than that ordinarily prevailing in the atmosphere, excluding liquid particles from the air supplied to the products to a suincient extent so that the products are not kept wet, and returning a portion of said air to be re-treated, the products and the body of air above them being shielded to a sufiicient extent, and the treated air being supplied at a suilcient rate, to maintain the relative humidity of said body of air substantially above that ordinarily prevailing in the atmosphere.

7. A method of conditioning products on display that comprises shielding the products and a body of air above them against the entry of atmospheric air without materially impairing the free accessibility of the products, refrigerating atmospheric air and discharging it among the products, and withdrawing, refrigerating and recirculating to the products air from said body of air, the products and said body of air being shielded to a sufficient extent, and the refrigerated air being supplied at a 'suiicient rate, to maintain the temperature of said body of air substantially below that of the atmosphere, and a suilicient volume of air being recirculated from said body of air to prevent the refrigerated air from undergoing a material temperature rise as it passes among the products.

KEITH W. HALL.

DONALD W. MCCREADY. 

